Apparatus for control of highway crossing gates



Feb. 10, 1948. c. 1.. GOODLIN APPARATUS FOR CONTROL 0F HIGHWAY CROSSINGGATES Filed Feb. 11, 1944 3 Sheets-Sheet l 6 013? 6 1 M906 cmzlmz I 0 22 W@ H x 2 G l I 1 w Jun WW W INVENTQR C 01! (70006112. BY Z Z 1 HIJ"ATTORNEY Feb. 10, 1948. c. 1.. GOODLIN 2,435,824

APPARATUS FOR CONTROL OF HIGHWAY CROSSING GATES Filed Feb. 11, 1944 3Sheets-Sheet 2 Gaee 67 MH [Yeofianzlrmf 4 T 3 F 'q 7P1? I" I0! T j I EDG X12 15' 1 tfsw 19 2. 3

INVENTOR 6 01"! Z. 80007122. BY QW HIJ" ATTORNEY Patented Feb. 10, 1943APPARATUS FOR CONTROL OF HIGHWAY CROSSINGIGATES Carl L. Goodlin, PennTownship, Allegheny County, Pa., assignor to The Union Switch & SignalCompany, Swissvale, Pa., a corporation of Pennsylvania ApplicationFebruary 11, 1944, Serial No. 521,896

6 Claims. (01. 318-286) My invention relates to apparatus for control ofhighway crossing gates, and more particularly to apparatus for automaticcontrol of highway crossing gates.

An automatic highway'crossing gate is ordinarily controlled by trainsthrough the medium of track circuits. The gate arm is latched in araised or non-obstructing position as long as the approach tracksections are unoccupied and is moved to a lowered or obstructingposition across the highway in response to a train entering an approachtrack section. When a train has passed beyond the intersection, the gatearm is raised to its non-obstructing position unless a second train orsome other trafilc condition makes it unsafe for highway traflic to passover the intersection. Such automatic control of a highway crossing gatemust include safeguards wherewith the lowering of the gate arm is notprevented by high winds or other conditions, and mechanical shock andrebound of the arm at the lowered position are avoided. Also, a circuitarrangement that is reliable, eflicient and of minimum structure isessential.

In view of such circumstances, a feature of my invention is theprovision of improved apparatus for control of highway crossing gates.

A further feature of my invention is the provision of control apparatusfor highway crossing gates incorporating novel and improved means forpower driving the gate arm both up and down, to deenergize the slotmagnet while the motor is operated to drive the gate down, to cushionthe movement of the gate arm at the lowered position, to avoid loweringthe gate arm from an intermediate position and to minimize the circuitand control apparatus without sacrifice of safety and efiiciency.

Other features, objects and advantages embodying my invention willappear as the specification progresses.

The above features, objects and advantages of my invention I attain byproviding a novel and improved arrangement of circuits and apparatus fora gate mechanism which includes a motor, a slot magnet and a circuitcontroller. The motor is operatively connected through a suitable geartrain to the gate arm which is movable between a lowered or obstructingposition and a raised or non obstructing position. The gate iscounterbalanced for the arm to gravitate to its lowered position but Ipreferably provide a reversible motor which is reversibly nergizedthrough a pole changing means to power drive the gate arm up and downaccording to the position of the pole changing means as predeterminedbya main control device. That is, the motor is operated in one directionin opposition to the bias to raise the gate arm and is operated in theopposite direction to aid the bias in the lowering of the gate arm. Inthe raising of the gate arm the motor is disconnected from the currentsource at a contact of the controller opened at substantially the fullraised position of the arm. In the lowering of the arm, the motorpreferably is supplied with power during a preselected first portion ofthe movement, and is disconnected from the current source and isincluded in a low resistance circuit path or snubbing circuit during thefinal portion of the lowering movement to eifect a dynamic braking, suchswitching of the motor circuits being accomplished through the medium ofcontacts of the circuit controller. In this way the lowering of the armis not prevented or delayed due to high winds and other conditions thatmay oppose the gravity bias and mechanical shock and rebound of the armat the lowered position are avoided.

Again, the counterbalance of the arm may be such that the motor need notbe powered only for a preselected portion of a downward movement andthen disconnected from the current source and the arm allowed tocontinue the movement under the force of the bias, the snubbing" circuitbeing omitted. Preferably the control circuits would include a stickcircuit arrangement wherewith once the raising of the gate arm isinitiated the motor is operated independent of the main control untilthe full raised position is reached, at which point the main control isagain made eifective. This prevents the gate arm from being lowered froman intermediate position in front of or on top ofa highway vehicle thatmay have started across the intersection upon the driver observing thegate arm starting to raise.

The slot magnet is preferably of the double winding type having aholding winding and a pick-up winding, the magnet armature being liftedto its latching position only when both windings are energized butretained at its latching position by the energization of the holdingwinding alone. The holding winding is controlled through a contact ofthe main control device and current is removed from the slot magnet atthe same time current is supplied to the motor to drive the ate armdownward. This prevents the slot latch from being forced in its releasedposition by the motor. The circuit for the pick-up winding is carriedthrough two controller contacts in series, the first one of which twocontacts is the contact used to open the motor circuit at the raisedosition, The second one of these two contacts is closed just shortlybefore the first mentioned contact is opened. This first controllercontact is of a construction that it is reclosed during the lowerinmovement of the arm at a position further removed from the raisedposition than the point at which such contact is opened during theraising of the arm and the point at which it is reclosed is madesubsequent to the openin of the second one of the two contacts. In thisway energization of the pick-up winding before the motor is energized toraise the arm is avoided in case the arm is being lowered and the maincontrol is changed to that for raising the arm. Thus, the motor is madeto take the shock and stress of arresting the lowering movement of thegate arm rather than the slot magnet when a change of control occurswhile the arm is being lowered.

Again, the snubbing circuit includes a contact which is held pen whenthe motor is powered to drive the gate arm downward as well as a contactheld open when the motor is powered to raise the arm.

Furthermore, when the gate mechanism is of the type provided with a casesuitable for housing relays, I locate one or two of the control relaysin the mechanism to minimize the circuit wiring.

I shall describe three forms of apparatus embodying my invention, andshall then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1, 2 and 3 are diagrammatic viewsshowing three different forms of apparatus for automatic control ofhighway crossing gates by trains, and each of which forms of apparatusembodies my invention. Fig, 4 is a chart showing the positions at whichcontroller contacts of the gate mechanisms of Figs. 1, 2 and 3 areopened and closed.

In each of the several views like reference characters are used todesignate similar parts.

It is to be understood that apparatus embodying my invention is notlimited to automatic control of highway crossing gates by trains and itis useful with apparatus where the gate is manually controlled and wherethe gate is controlled in part manually and in part by railway traflic.

Referring to Fig. l, the reference characters Ia and lb designate thetrack rails of a railway intersected at grade by a highway H, and atwhich intersection two highway crossing gates GI and G2 are located. Thetrack rails are formed by the usual insulated rail joints with two tracksections, one on each side of the highway, a section D-E being formed tothe left of the highway H as viewed in Fig. 1, and a section E--F beingformed to the right of the highway. In other words, section DE is anapproach section for eastbound trains and section EF is an approachsection for westbound trains,

Each track section D-E and E-F is provided with a track circuit whichincludes a current source, such as a battery III, connected across therails at one end of the section, and a winding of an interlocking relayIR connected across the rails at the other end of the section, windingII of relay IR being included in the track circuit of section DE andwinding I2 of relay IR being included in the track circuit for sectionE-F. The connections of windings II and I2 to the track rails are thoseof common practice to provide the so-called extended shunt protection.

as will be readily understood by an inspection of 4 the drawings, andthese connections need not be described in detail since they form nopart of my invention.

Highway crossing gates GI and G2 are shown conventionally and arelocated one on each side of the railway tracks and are adaptable ofbeing operated in a manner such that their respective gate arms I3 andI4 are moved between a lowered position where the arm extendshorizontally across at least a portion of the highway H and a raisedposition where the arm extends substantially vertical. Each crossinggate GI and G2 is provided with an operating mechanism which may be anyone of several well-known types and preferably the two mechanisms are oflike construction. In the present embodiment of the invention themechanism for each gate GI and G2 is similar to that shown and describedin Letters Patent of the United States No. 1,138,087, granted to John P.Coleman on May 4, 1915, for Railway signals, and to which patentreference is made for a full understanding of the construction of suchmechanism. In the application the gate arm is an extended form of thesemaphore of the patent.

The mechanism and control for gate GI only is shown in the drawing forthe sake of simplicity since the two gates are alike and the mechanismand control of gate G2 would be a duplication of that for gate G I.

Looking at the gate GI mechanism of Fig. 1, a motor MI, slot magnet SMand a circuit controller CI are among the essential elements of themechanism. Motor MI is a direct current reversible motor having anarmature I5 and a field winding I6. Motor MI is operatively connectedbysuitable drive mechanism (not shown) to the gate arm I3 and which drivemechanism may be similar to that disclosed in the aforementioned Colemanpatent. The mechanism of gate GI is counterbalanced for arm I3 to begravity biased to the lowered position. Motor MI when supplied withcurrent which flows in its armature in one direction with respect to theflow of current in the field winding is operated as required to raisethe arm I3 against the bias force. When motor MI is supplied withcurrent that flows in its armature reverse with respect to said onedirection, the motor is driven as required to lower the arm, the motorMI aiding the bias force. In the following description the position ofthe gate mechanism corresponding to the lowered or obstructing positionof the gate arm will be at times referred to as a zero degree orobstructing position, and the position of the gate mechanismcorresponding to the raised or non-obstructing position of the gate armwill be at times referred to as a degree or non-obstructing position. Itwill be understood, however, that apparatus'embodying my invention isnot limited to a 90 degree movement of the gate arm. Also, it is to beobserved that the arm may be provided with a slightly greater than 90degree movement in order to permit adjustment.

Slot magnet SM includes a holding winding II, a pick-up winding I8 andan armature 35. As fully explained-in the aforementioned Coleman patent,the armature 35 when picked up latches the gate arm at the 90 degreeposition, and when the magnet is deenergized and the armature released,the gate mechanism is free to move toward its zero degree position. Thearrangement is such that the armature 35 is raised to its attracted andlatching position only when both windings I1 and I8 are energized. butonce picked'up the armature is held at its latching position by theenergization of the holding winding I! alone.

Controller Cl includes a series of contacts 2, 3, 4, 5 and 6, which areshown conventionally for the sake of simplicity. The controller Cl isoperatively connected to the gate arm through the gate mechanism in sucha manner that the contacts are opened and closed as indicated by thechart of Fig. 4. It is to be observed that contact 4 of the controlleris opened at the 89 degree position in the raising of the gate arm andis not reclosed until the 83 degree position of the,

arm when the arm is being lowered. The function of such construction ofcontact 4 will be pointed out more specifically later in thedescription. The construction of contact 4 may be that disclosed andclaimed in Letters Patent of the United States No. 2,363,936, grantedNovember 28, 1944, to H. L. Bone, for Circuit controllers.

The control means for the gate Gl of Fig. 1 includes a track repeaterrelay or control device TPR, a control relay XR and two other relays 'DNand SN. Repeater relay TPR is a slow release direct current relayenergized by current supplied from a source, the terminals of which areindicated at B and C, the energizing circuit being completed throughflagman contacts l9 and 20 in series of the interlocking relay IR. Itfollows that when both sections D-E and E-F' are unoccupied or eithersection is occupied by a train receding from the intersection and theother track section is unoccupied, repeater relay TPR is energized andpicked up, but that when either section is occupied by a trainapproaching the intersection the relay TPR is deenergized. Repeaterrelay TPR governs the control relay XR and the holding winding I! of theslot magnet by obvious circuits which include front contacts 9' and 2|of relay TPR, respectively. The two relays DN and SN are preferably ofthe type that permits their being located in the gate mecham'sm. Controlrelay XR governs the two relays DN and SN, the pick-up winding I8 ofslot magnet SM and the motor operating circuits, the control of thesedevices being effected in part through contacts of the circuitcontroller Cl. It is-believed that these various circuits will best beunderstood by a description of the operation of the apparatus of Fig. 1.Y

'Normally, that is, when both track sections D-E and E-F are unoccupied,the interlocking relay IR is picked up to close the circuit for repeaterrelay TPR and that relay is picked up to close front contacts 9 and 2|and thereby com-,

plete'the circuits for the control relay XR and the holding winding llof the slot magnet. Such energization of the slot magnet winding iseffective to retain the gate mechanism at its 90 degree position, itbeing understood that the mechanism has been operated to that positionin a manner to appear shortly.

Assuming an eastbound train enters the approach section D'--E, winding Hof the interlocking relay IR is shunted and its armature is released toopen front contact [9 and close back contact'22, The opening of frontcontact l9 deenergizes repeater relay TPR and that relay releases at theend of its slow release period. In accordance with standard practice,the closing of back contact 22 of relay IR completes a warning signalcircuit by which a warning bell or lamp, or both, are operated to warnhighway users that a: train is approaching and that the gate arm isabout to be lowered. The remaining portion of,

. warning signal would be set into operation immediately upon the trainentering the section D-E, whereas the release of relay TPR which governsthe lowering of the gate is delayed due to the slow release periodprovided for relay TPR.

The release of relay TPR to open front contacts 9 and 2| dcenergizescontrol relay XR and holding winding 11 of the slot magnet with theresult that relay XR is released and the gate arm is unlatched and isfree to be moved to its hori-.

zontal position. Since the gate is normally counterbalanced its arm willgravitate toward its.

lowered position by virtue of its own weight However, the release ofrelay XR to close backcontacts 23 and 24 completes a circuit for relayDN and prepares an operating circuit for the motor MI. The circuit forrelay DN extends from terminal B of the current source through backcontacts 23 and 24 in multiple of relay XR, controller contact 3 closedfor a preselected portion of the downward movement of the gate arm,"

and winding of relay DN to terminal C. Relay DN is energized and pickedup to complete an extension of the circuit which forms the motor'circuit, and current flows from terminal B through back contacts 23 and24 in multiple, controller contact 3, front contact 25 of relay DN,armature 1-5 of motor Ml from right to left as viewed in Fig. 1, frontcontact 26 of relay DN and motor field winding IE to terminal C. Theconnections for the motor Ml are such that the motor is now energizedand operated as required to power drive the gate arm in its downwarddirection, such operation of the motor being effective to move the gatearm even though a high wind and other conditions may exist that wouldtend to retain the arm at the raised position against the bias force.When the 45 degree position is reached and controller contact 3 isopened, this circuit for relay DN and motor Mt is opened, but the gatearm continues to move toward its lowered position under the influence ofthe bias.

cult is completed from the left-hand terminal of armature 15 of motor Mlthrough back contact 21 of relay DN, back contact 29 of relay SN, aresistor 30, field winding 16, and back contact 28 of relay DN to theright-hand terminal of armature I5. Since armature I5 is now driven bythe bias force the motor Ml functions as a generator. to brake themovement of the gate arm, the brak-z ing force exerted beingpredetermined by the adjustment of resistor 30.

' At the 10 degree position in the lowering movement of the gate, thecontact 2 of circuit OOH? troller Cl is closed and a short circuit pathcan be traced from the left-hand terminal of armature l5 of motor M'lthrough back contact 2! of relay DN, back contact 29 of relay SN,controller contact 2, field winding l6, back contact 28 of relay DN andto the right-hand terminal. of armature 15. Since motor MI is nowsubstantially short circuited the dynamic braking is increased so thatat the zero degree position of the arm no severe mechanical shock orrebound of the arm takes place.

The gate arm remains at its lowered position until the train passesbeyond the intersection and the rear end of the train vacates sectionD-E anti gized. The closing of front contact |9c winding completes thecircuit for relay TPR and that relay isenergized to close front contacts9 and II and complete the circuits for control relay XR and'winding llof the slot magnet. With control relay XR picked up to close frontcontacts 3| and 32, a circuit is formed for relay SN and a motoroperating circuit is prepared, thecircuit for relay SN includingterminal B, front contacts 3| and 32 in multiple, controller contact 4,winding of relay SN and terminal C, and relay SNis picked up to closefront contact 33. The closing of front contact 33 of relay SN completesan extension-of the circuit which forms a motor operating circuit sothat current flows from terminal B through front contacts 3| and 32 inmultiple, controller contact 4, front contact 33 of relay-SN, backcontact 21 of relay DN, armature of the motor from left toright, backcontact 28 of relay DN, and motor field winding IE to terminal C. Themotor M| is now operated as required to raise the gate arm against thebias force.

When the arm is raisedto'the 86 degree position thecontroller contact .5is closed and current flows from terminal B through front contacts 3|and 32 of relay XR in multiple, controller contacts 4 and 5 in seriesand pick-up winding I8 of slot magnet SM to terminal 0, and the armature35 of the slot magnet is raised to its latching position since bothwindings l1 and I8 are now energized.

At the 89 degree position inthe raising movement of the gate,thecontroller contact 4 is operated to open the circuitsfor relay SN,motor M| and pick-up-winding l8, withgthe result relay SN is released,the operation of the motor is discontinued and the gate arm is retainedlatched in its raised position due to the energization of the holdingwinding II.

It is to be pointed out specifically that the circuit for energizingpick-up winding l8 of the slot magnet includes the controller contacts4' and 5 in series, the circuit being-completed between the 86 degreeand the 89 degree movement in the raising of the gate arm. Then, whenthe gate isbeing lowered, contact'5 is opened at the 86 degree positionbut contact 4, due to-its construction, is not reclosed until the 83degree position, and the circuit for winding la is not closed at anypoint during the'loweringcf'the arm.,

Consequently, if the gate is being lowered and the main control shouldbe changed to that for raising the arm, the stress due to stopping themovement of the arm is taken up by the motor and not by the slot magnet,and which stress might be great enough to damage the slot magnet.

It is also to be observed that when control relay XR is picked up inresponse to the picking up of relay 'IPR, a stick circuit is completedfor relay XR, which circuit extends from terminal B through controllercontact 6, front contact 34 of relay XR and winding of that relay toterminal C. Consequently, once relay XR is picked up by the maincontrol, that is, through contact 9 of relay 'IPR, and the gate arm isstarted to raise, relay XR is retained energized independent of relayTPR, and the raising movement of the gate is continued until the 89degree position is reached and controller contact 8 is opened. In otherwords, once the raising of the gate arms is started subsequent to atrain passing beyond the intersection, the gate arm is raised to itsverticalposition before it can be again lowered in response to a secondtrain entering the approachsection; In this way the gate arm isnotlowered from an intermediate position to come .downjon top of somehighway vehicle that has started.

over the intersection after waiting for the first train to pass.

Again, it is to be observed that the snubbing" circuit is held open atback contact 21 of relay DN during the lowering of the arm under theinfluence of motor MI, and is held opened at back contact 29 of relay SNduring the operation of the motor in raising the gate arm.

It is apparent that the operation of the apparatus of Fig. 1 for awestbound train is similar to that described for an eastbound train,except that the relay TPR is controlled at front contact 20 of windingI: of the interlocking relay.

In Fig. 2, the track layout and the control of repeater relay 'I'PR,control relay XR. and hold ing winding ii of slot magnet SM are the sameas in Fig. 1 except the stick circuit for control relay XR, is omitted.The circuit for relays DN and SN and motor MI of Fig. 2 are arranged forthe two relays DN and SN to function asa pole changing means, thesnubbing circuit for the motor being omitted. It is believed that thecircuits of Fig. 2 will best be understood by a description of theoperation of the apparatus.

Normally, that is, when both sections D E and E F are unoccupied, therepeater relay TPR.

is picked up toclose front contacts 9 and 2| and the control relay XRand holding winding I! are energized, the energization of winding 11latching the gate arm at the degree position.

An eastbound train entering section D-E of Fig. 2 to shunt winding ofthe interlocking relay brings about the deenergization of repeater relay'IPR and the operation of the warning signal. Relay TPR releases at theend of its slow release period, to cause control relay XR and holdingwinding I! who deenergized with the result the gate arm is unlatched andis free to be moved to its lowered position. The release of relay XR toclose back contacts 23 and 24 completes a circuit which includes inseries the wind ing of relay SN and motor Ml, such circuit extendingfrom terminal B through back contacts 23 and 24 of relay XR in multiple,controller contact 3, winding of relay SN, armature I5 02 motor Ml fromright to left, back contact 36 of relay DN and the motor field windingHi to terminal C. Relay SN is now picked up to open back contact 31 andthe motor MI is energized as required to drive the gate arm towards itslowered position. With controller contact 3 adjusted to open at 45degrees as indicated by the chart of Fig. 4, the relay SN and motor Mlbecome de energized at this point in the lowering orthe gate arm and thegate arm would then continue in its downward movement under theinfluence oi the bias. It is apparent, however, that controller contact3 can be adjusted to open at some other position and the motor made togovern any preselected portion of the downward movement.

When the eastbound train passes beyond the intersection; to vacatesection D- E causing winding ll of relay IE to be reenergized and bringabout the reenergization of repeater relay TPR, the control relay XR andthe winding, H of the slot magnet are energized. With relay -XR pickedup to close front contacts 3| and 32,

acircuit is completed for relay DN in series with the motor, currentflowing from terminal B through front contacts 3| and 32 in multiple ofrelay XR, controller contact Lwinding of relay DN, armature "l5 fromleftto right, back (:On-

tact 31 of relay SN and field winding l6 of the motor to terminal C.Relay DN is now picked up to open back contact 36 and close frontcontact 38 and the motor MI is operated as required to raise the gatearm. At the 86 degree position the controller contact 5 is closed and acircuit is formed for the pick-up winding I8, current flowing fromterminal B through front contacts 3! and 32 in multiple of relay XR,controller contacts 4 and 5 in series, front contact 38 of relay UN andwinding l8 to terminal Both windings I1 and I8 being now energized, thearmature 35 of the slot magnet is raised to its latching position. Atthe 89 degree position of the movement, the controller contact 4 isopened so that relay DN, motor MI and winding l8 are all deenergizedleaving the gate arm latched at the raised position due to theenergization of the holding winding I! of the slot magnet. Although thestick circuit for relay XR is omitted in Fig. 2, it is obvious that suchstick circuit arrangement can be included in the same manner as it isincluded in Fig. 1, and when thus added to the apparatus of Fig. 2 theapparatus would function in the raising of the gate arm independent ofthe main control in the same way as described in connection with Fig. 1.

Furthermore, with controller contact 4 adjusted to open at 89 degrees inthe raising of the arm and to be reclosed at the 83 degrees position inthe lowering of the arm, the circuit for pick-up winding 18 of the slotmagnet is held open during the lowering movement and energization ofmagnet SM cannot take place if a change occurs in the main control tobring about the raising of the arm when the arm is being lowered andstresses created due to stopping the movement of the arm do not fallupon the slot magnet structure. v

It is clear that the apparatus of Fig. 2 will operate in response to awestbound train in a manner similar to that described in connection withan eastbound train.

Referring to Fig. 3, the apparatus is similar to that of Fig. 2 exceptthe second relay SN is omitted and the pole changing of the motorcircuit is effected at contacts of the control relay XR Normally, thatis, when the sections D-E and E-F of Fig. 3 are unoccupied and trackrepeater relay TPR is picked up, the circuits for control relay XR. andholding winding H of the slot magnet are completed so that the gate islatched at the 90: degree position, the same as explained in theprevious cases.

When an eastbound train enters section D-E 'of Fig. 3, winding 1 I ofrelay IR is shunted causing in turn the repeater relay TPR to bedeenergized and the warning signal to be operated. Release of relay TPRat the end of its slow release period causes control relay XR andwinding I! of the slot magnet to be deenergized and the gate isunlatched and free to be moved to its lowered position. With relay XRreleased current flows from terminal B through back contact '23 of relayXR, controller contact 3, Winding of relay DN, armature I 5 of motor Mlfrom right to left, back contact 24 of relay XR, and field winding iiiof the motor to terminal C.

Relay DN is picked up to open its back contact 39 interposed in thecircuit for winding i8 of the slot magnet and motor MI is operated asrequired to drive the gate arm in a downward direction. At somepreselected position in the lowering of the arm and here shown as at the10 degree position, controller contact 3 is opened to deenergize relayDN and motor MI and further movement of the gate arm is caused by thebias force.

When the eastbound train vacates section D-E, so that winding ll of heinterlocking relay is reenergized to bring about the energization ofrepeater relay TPR, control relay XR and winding I! of the slot magnetare supplied with current. With relay XR picked up current flows fromterminal B through front contact 3| of relay XR, controller contact 4,armature l5 of motor Ml from left to right, front contact 32 of relay XRand motor field winding IE to ter-. minal C, and the motor is operatedas required to raise the arm. At the 86 degree position of the gate armthe controller contact 5 is closed, and current flows from terminal Bthrough front ccntact ii of relay XR. controller contact 4, back contact33 of relay DN, controller contact 5 and winding i8 of magnet SM toterminal C. Since both windings H and I8 of the slot magnet are nowsupplied with current its armature 35 is picked up so that whencontroller contact 4 is opened at the 89 degree position to open themotor circuit, the arm is latched at the raised position due to theenergization of the holding winding I7. Again it is to be pointed outthat due to the circuit for winding I8 including the two controllercontacts 4 and 5" in series, and the construction of contact 4, windingI 8 cannot be energized during the time the motor MI is operated topower drive the gate arm in a downward movement. I

It is apparent from an inspection of Fig. 3 that the apparatus willoperate in substantially the same manner for a westbound train.

The apparatus here disclosed has the advantages that the gate arm isdriven both up and down, and the downward driving of the arm by themotor is discontinued at a preselected point and dynamic brakingeffected so that severe mechanical shock and rebound of the arm at thelowered position are avoided. Again, the slot magnet cannot be energizedduring the lowering movement of the gate armand stresses of themechanism effected when there is a reversal in the main control of thegate during a lowering movement are taken up by the motor and not by theslot magnet. Again, the raising of the arm once initiated may becontinued until the full raised movement of the arm is effected and thearm is not lowered from an intermediate position without due warning tothe highway users. Also, the circuit arrangement is minimized and madesimple without sacrificing safety and reliability.

Although I have herein shown and described only three forms of apparatusfor control of highway crossing gates embodying my invention, it isunderstood that various changes and modifications may be made thereinwithin the scope pombination' comprising, a first and a secondconobstructing position and the obstructing position respectively; othercircuit means including in series said front contact of, said secondcontrol relay, said first controller contact and a third controllercontact to energize said pick-up winding, said first controller contactoperable to be opened subsequent to the closing of said third contactwhen the mechanism is driven toward the non-obstructing position and tobe reclosed subsequent to the opening of said third contact when themechanism is driven toward the obstructing position whereby stresses ofthe mechanism when there is a reversal of the motor during a movementtoward the obstructing position are taken up by the motor, a shortcircuiting path including a fourth contact of said controller closedsubsequent to the opening of said second contact connected across themotor to provide dynamic braking during a preselected portion of themovement of the mechanism toward the obstructing position, and means toat times energize said first control relay.

2. In control apparatus for a gate mechanism biased toward a zero degreeposition and operable to a 90 degree position and having a reversiblemotor adapted when energized to drive the gate mechanism and acontroller actuated by movement of the gate mechanism, the combinationcomprising, a control relay, a relay DN, a relay SN, a first circuitincluding a front contact of said controlrelay and a first contact ofsaid controller to energize said SN relay, an extension of said firstcircuit including a front contact of said SN relay and back contacts ofsaid DN relay to energize said motor to operate the gate mechanism tothe 90 degree position, a second circuit includ .ing a back contact ofsaid control relay and a second contact of said controller to energizesaid DN relay, an extension of said second circuit includingfrontcontacts of said DN relay to energize the motor to operate the gatemechanism a preselected distance toward the zero degree position aspredetermined by the opening of said second contact; a low resistancecircuit including a resistor, a back contact of said DN relay and a backcontact of said SN relay connected across said motor to provide dynamicbraking of the motor; a short circuiting path including a back contactof each of said DN and SN relays and a third contact of said controllerconnected across the motor to provide heavy dynamic braking of themotor, and circuit means to at times energize said control relay.

3. In control apparatus for a gate having a mechanism including areversible motor adapted .to drive the gate mechanism, a circuitcontroller actuated by the gate mechanism and a slot magnet providedwith a holding and a pick-up winding and made effective by theenergizing of its windings, the combination comprising, a control,

a pole changing and another relay; means to at times energize saidcontrol relay and said holding winding, a first circuitincluding a frontcontact of said control relay and a first contact of said controlleropened at a non-obstructing position of the gate to energize said otherrelay, an extension of said first circuit including a front contact ofsaid other relay and back contacts of said pole changing relay toenergize said motor to operate the mechanism to the non-obstructingposition; a branch circuit path for said first circuit and includingsaid front contact of the control relay, said first contact of thecontroller and a second contact of the controller to energize saidpick-up winding; a second circuit including a back contact of saidcontrol relay and a third contact of said controller opened at apreselected point in the movement of the gate to an obstructing positionto energize said pole changing relay, an extension for said secondcircuit including front contacts of the pole changing relay to energizesaid motor to operate the mechanism toward the obstructing position to apoint preselected by the opening of said third controller contact; andother circuit means in eluding a back contact of said pole changingrelay, a back contact of said other relay and a fourth contact of saidcontroller to provide dynamic braking of the motor.

4. In control apparatus for a gate mechanism operable to an obstructingand to a non-obstructing position and having a reversible motor adaptedwhen energized to drive the mechanism, a circuit controller actuated bymovement of the mechanism and a double winding slot magnet madeeffective by the energizing of its windings, the combination comprising,a first and a second control relay, circuit means including a frontcontact of said first control, relay to energize said second controlrelay and a holding winding of said slot magnet, an operating circuitmeans including a front and a back contact of said second control relayto reversibly energize said motor to drive the gate mechanism eithertoward its non-obstructing or obstructing position according as saidsecond control relay is picked up or released, a first and a secondcontact of said controller interposed in said operating circuit means todeenergize saidmotor as it drives the gate mechanism toward the nonobstructing and obstructing positions respectively; other circuit meansincluding in series said front contact of said second control relay,said first contact of said controller and a third contact of thecontroller to energize a pick-up winding of said slot magnet; saidcontroller of a construction for said third controller contact to beclosed prior to the opening of said first controller contact when themotor is driving the mechanism toward the non-obstructing position andfor said first controller contact to be reclosed subsequent to theopening of said third controller contact when the motor is driving themechanism toward the obstructing position, and

means to at times energize said first control trol relay and saidholding winding; a first operating circuit including a front contact ofsaid second control relay, first contact of said controller, a windingof said first pole changing relay, said motor and a back contact of saidsecond pole changing relay to energize the motor to drive the mechanismtoward the nonobstructing position; a second operating circuit includinga back contact of said second control relay, a second contact of saidcontroller, a winding of said second pole changing relay, said motor anda back contact of said first pole changing relay to energize the motorto drive the mechanism toward the obstructing position; another circuitincluding said front contactof said second control relay, said firstcontroller contact, a third controller contact and a front contact ofsaid first pole changing relay to energize said pick-up winding of theslot magnet, and means to at times energize said first control relay.

6. In control apparatus for a gate mechanism operable to an obstructingand a nonobstructing position and having a reversible motor adapted whenenergized to drive the mechanism, a circuit controller actuated bymovement of the mechanism and a slot magnet provided. with a holding anda pick-up winding and made effective by the energizing of its windings,the combination comprising, a first and a second control relay, anotherrelay, means including a contact of said first control relay to energizesaid second control relay and said holding winding; a first operatingcircuit including front pole 14 changing contacts of said second controlrelay and a first contact of said controller to energize said motor todrive the mechanism toward the non-obstructing position; a secondoperating circuit including back pole changing contacts of said secondcontrol relay, a second contact of said controller, and a winding ofsaid another relay to energize the motor to drive the mechanism towardthe obstructing position; another circuit including one of said frontpole changing contacts of the second control relay, said firstcontroller contact, a back contact of said another relay and a thirdcontact of said controller to energize said pick-up winding; and meansto at times energize said first control relay.

CARL L. GOODLIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,824,152 Howe Sept. 22, 19311,893,824 McWhirter Jan. 10, 1933 2,137,196 Sampson Nov. 15, 19382,163,838 Hines June 27, 1939 2,219,757 Schleicher Oct. 29, 19402,220,154 Howe et al Nov. 5, 1940 2,220,162 Lindner Nov. 5, 19402,295,419 Miskelly Sept. 8, 1942 2,312,758 Goodlin Mar. 2, 19432,340,816 McCann Feb. 1, 1944 2,368,745 Crago Feb. 6, 1945

